466 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 10 



become noticeable before the middle of June or early July and are not 

 abundant before mid-July. If only a very few sui~vive the winter this 

 would account for their later seasonal appearance. 



To test the ability of adult flies to live throughout the winter the 

 following experiments were conducted: 



Just before frost appeared, on October 31, a quantity of larvse and 

 puparia were collected and about two hundred were placed in each of 

 several jars, containing a little moist soil covered with a layer of fresh 

 manure. These jars were placed in breeding cages and the cages in 

 different places, where conditions were such as have been thought 

 suitable for overwintering of the flies. As soon as the flies had emerged 

 they were fed regularly with fresh banana and water. The places 

 chosen were (1) a cellar where the temperature averaged 62°, the 

 lowest recorded being 50°; (2) a stable at the dairy barn, where the 

 temperature never went below the freezing point and only once during 

 the winter approached that point, averaging 45° ; (3) an unheated store- 

 room. Heat entered the latter through an open transom, keeping 

 the temperature above freezing. In this room a large number of flies 

 were also set free. In all six cages of flies were used in this test. 

 Adults began to emerge November 11. In the cellar they were all 

 dead by November 23. In the stable a few survived until February 6. 

 In the storeroom a sudden fall in temperature on December 14 caused 

 the death of all the flies. No thermometer was available to record 

 the temperature, but it was above freezing. Several cages had also 

 been prepared, packed with folds of cheesecloth in which flies could hide 

 away. These were placed in various stable lofts and covered with hay. 

 Where the temperature of the loft was that of the outdoors, the flies 

 died as soon as the temperature approached freezing; in the lofts where 

 the temperature remained higher the flies survived until early December 

 by which time the weather had become cold enough to lower the 

 temperature of the loft to near the freezing point. 



During the summer of 1914 several attempts were made to find the 

 reaction of various stages of the house-fly to low temperatures. As 

 no constant temperature apparatus was at our disposal we secured 

 the privilege of using a cold storage plant in town. Temperatures of 

 12°, 30° and 40° F. were available. Week intervals were necessary 

 between examinations. Adult flies were placed in quart fruit jars 

 containing strips of paper for supports and with cheesecloth tied over 

 the top; larvse and pupse were placed in moist soil and manure in 

 wooden boxes 3| x 2f x 2 inches in size. Several of these boxes were 

 placed inside a larger one for convenience in handling. Twenty-five 

 adults were in each jar and 100 larvse or pupse in each box. Exposures 

 at 12° F. for one week were fatal to adults, but one male survived 



